U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
Crash modification factors (CMFs) support a number of safety-related activities in the project development process. The CMFs in Practice Series includes five separate guides that identify opportunities to consider and quantify safety in specific activities, including roadway safety management processes, road safety audits, design decisions and exceptions, development and analysis of alternatives and value engineering. The series also includes reference documents that provide background information on crash modification factors and safety performance functions.
Introduction to Crash Modification Factors
Defines crash modification factor and highlights key factors to consider when applying CMFs.
Introduction to Safety Performance Functions
Defines safety performance functions and highlights various application scenarios, as well as calibration requirements.
CMFs in Practice: Quantifying Safety in the Roadway Safety Management Process
When used in the roadway safety management process, CMFs can help teams select countermeasures and prioritize projects through an economic evaluation. A case study highlights the Strategically Targeted Affordable Roadway Solutions program in Virginia.
CMFs in Practice: Quantifying Safety in Road Safety Audits
CMFs can be applied in the Road Safety Audit (RSA) process to quantify the safety effects of treatments and justify RSA team's suggestions to the project owner. A case study shows how CMFs were applied by the Michigan Department of Transportation in a RSA.
CMFs in Practice: Quantify Safety in Alternatives Development and Analysis
CMFs can be applied in the analysis of alternatives to quantify the safety performance of alternative designs. In the first case study, to accommodate growing development in the Castle Rock, Colorado, area, the Colorado Department of Transportation considered two intersection designs as partof a new interchange on I-5. Another case study illustrates how CMFs were used in conjunction with SPFs by the Arizona Department of Transportation in the development and analysis of alternatives.
CMFs in Practice: Quantify Safety in Design Decisions and Exceptions
CMFs can be applied to quantify the safety impacts of individual design elements and evaluate the overall impact of design exceptions on the safety performance of a facility. One case study illustrates how CMFs were applied by the California Department of Transportation to estimate the safety impacts of proposed engineering improvements after 24 collisions occurred over a three-year period on a section of US 199. Another case study illustrates how CMFs were applied in conjunction with safety performance functions (SPFs) by the Missouri Department of Transportation to quantify the safety performance of various design elements.
CMFs in Practice: Quantify Safety in Value Engineering
CMFs can be applied in the Value Engineering process to explicitly consider and quantify safety impacts of opportunities identified by the study team. A case study illustrates how CMFs were applied in conjunction with SPFs by the Missouri Department of Transportation to quantify the safety impacts of opportunities related to the crosssection and roadside design.